’Nuclear butterflies’ cause stir: Mutant insects traced to Fukushima

The Fukushima Daiichi nuclear plant disaster is causing "nuclear butterflies" to emerge across Japan. According to a study published in an online magazine, experts believe radiation fallout may have caused pale blue grass butterflies to undergo "physiological and genetic damage."

Monday, ABC News said that scientists looked at about 121 butterflies, two months after the nuclear disaster in Japan. What they found was astounding.

Of the insects captured, about 12% had smaller wings. However, when their offspring were born, the number increased another 5%.

Nuclear butterflies were even seen six months later after the Fukushima Daiichi nuclear plant disaster. About 28% had "abnormal traits," according to study authors. That number is expected to double by the next generation due to above-normal radiation fallout.

"At the time of the accident, the populations of this species were overwintering as larvae and were externally exposed to artificial radiation. It is possible that they ate contaminated leaves during the spring and were thus also exposed to internal radiation," said researchers in the study on the Fukushima Daiichi nuclear plant disaster.

Other than "nuclear butterflies" in Japan, small amounts of cesium were found in several bluefin tuna off San Diego’s coast last year. While the numbers are about 10 times higher than the year before, Japan officials say the radiation amounts are well below threats to human health.

The abnormalities, which the researchers traced to the radiation released from the nuclear power plant, include infertility, deformed wings, dented eyes, aberrant spot patterns, malformed antennas and legs, and the inability to fight their way out of their cocoons. The butterflies from the sites with the most radiation in the environment have the most physical abnormalities, the researchers found.

Butterflies from Fukushima, Iwaki and Takahagi showed wing size and shape deformations, including, respectively, a right hindwing that was much smaller than the left hindwing, folded wings, and rumpled wings